CVE-2021-35969 in Infinity
Summary
by MITRE • 01/15/2022
Pexip Infinity before 26 allows temporary remote Denial of Service (abort) because of missing call-setup input validation.
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Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2021-35969 affects Pexip Infinity versions prior to 26, representing a critical security flaw that enables attackers to execute temporary remote denial of service attacks through manipulated call setup inputs. This vulnerability stems from insufficient validation mechanisms during the initial call establishment phase, creating an exploitable condition that can disrupt legitimate communication services. The affected system operates within the unified communications and video conferencing domain, where reliable call setup processes are essential for maintaining service availability and user experience.
This technical flaw manifests as a missing input validation mechanism during the call setup process, which falls under the CWE-20 category of "Improper Input Validation." The vulnerability allows malicious actors to send specially crafted or malformed call setup requests that cause the system to abruptly terminate connections or enter unstable states. The absence of proper validation checks means that the system cannot adequately distinguish between legitimate and malicious inputs, leading to system instability and service disruption. The attack vector specifically targets the initial call establishment phase, making it particularly dangerous as it can affect the very foundation of the communication service.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall reliability and trustworthiness of the Pexip Infinity platform. When exploited, the vulnerability can cause temporary denial of service conditions that may affect multiple concurrent calls, leading to business continuity issues and user frustration. Organizations relying on this platform for critical communications may experience significant operational disruption, especially in environments where continuous availability is essential. The vulnerability's remote nature means that attackers can exploit it from external networks without requiring physical access or elevated privileges, making it particularly concerning for enterprise environments.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1499.004 which involves network denial of service attacks. The flaw represents a classic example of how insufficient input validation can create exploitable conditions in network services, particularly those handling real-time communication protocols. Security practitioners should note that the vulnerability affects the core call processing functionality, making it a high-priority target for remediation. The temporary nature of the denial of service means that while the impact may not be permanent, the frequency and duration of attacks can still cause substantial operational disruption and may serve as a precursor to more sophisticated attacks targeting the same system components.
Organizations should implement immediate mitigations including updating to Pexip Infinity version 26 or later, which contains the necessary input validation fixes. Network-level protections such as rate limiting and connection monitoring can provide additional defense-in-depth measures. Security teams should also implement proper logging and monitoring of call setup processes to detect anomalous patterns that may indicate exploitation attempts. The vulnerability highlights the importance of robust input validation practices in real-time communication systems and serves as a reminder that even seemingly minor validation gaps can lead to significant service availability issues. Regular security assessments and vulnerability management processes should be enhanced to identify similar input validation weaknesses in other communication infrastructure components.